Very possible to write this.
Take a look at an old event of mine, which recreates Christian titles, for an example of how to do it:
Christian Realm Revolters.
You will need to replace the tags, change christian to pagan in the triggers, and adjust the areas.
Here's a simple example (untested):
Code:
#############################
# The Mordvins #
#############################
province_event = {
id = 909041
trigger = {
condition = { type = area value = 579 } #Mordva
condition = { type = religion value = pagan }
condition = {
type = or
condition = { type = has_province_effect value = { revolt = yes } }
condition = { type = has_province_effect value = { looted = yes } }
}
condition = {
type = not
value = {
type = exists
value = MORD
}
}
condition = {
type = not
value = {
type = exists
value = RUSS # If Russia exists, it is assumed to have wiped out pagan resistance.
}
}
condition = {
type = not
value = {
type = ruler_religion
value = pagan
}
}
}
mean_time_to_happen = {
months = 72 #6 years
modifier = {
condition = { type = ruler_csc condition = { type = trait value = realm_duress } }
factor = 12 # half year
}
}
action_a = {
effect = { type = create_tag value = MORD }
effect = { type = prosperity value = 1 }
effect = { type = add_regiment culture = ugric_baltic strength = { archer_cav = 4000 light_cav = 2000 heavy_cav = 1000} }
effect = { type = add_regiment culture = ugric_baltic strength = { archer_cav = 4000 light_cav = 2000 heavy_cav = 1000} }
effect = { type = random
chance = 50
effect = { type = add_regiment culture = ugric_baltic strength = { archer_cav = 4000 light_cav = 2000 heavy_cav = 1000} }
}
}
}